CN103548237A - Electromagnetically-coupled state detection circuit, power transmission apparatus, contactless power transmission system, and electromagnetically-coupled state detection method - Google Patents

Abstract

Adopted is a configuration wherein a primary side Q-value of a circuit containing a primary side coil (15) that electromagnetically couples with a secondary-side coil, and power transmission efficiency between the primary side coil (15) and the secondary-side coil are measured, the power transmission efficiency is corrected with the Q-value of the primary side coil (15), and the state in which the primary side coil (15) is electromagnetically coupled to the secondary-side coil is detected on the basis of the obtained corrected value.

Description

Electromagnetic coupled state detection circuit, power transmission device, non-contact electric power conveying system and electromagnetic coupled condition detection method

Technical field

The disclosure relates to electromagnetic coupled state detection circuit, power transmission device, non-contact electric power conveying system and electromagnetic coupled condition detection method.

Background technology

In recent years, developed energetically the non-contact electric power conveying system of wireless power (that is, in non-contacting mode).The non-contact electric power carrying method of realizing that causes concern is magnetic resonance method.Magnetic resonance method is carried out electric power conveying by the electromagnetic coupled between transmission coil and receiving coil.By utilizing energetically resonance phenomena, magnetic resonance method is characterised in that, between power supply and power supply destination, the amount of shared magnetic flux can be very little.

According to the electromagnetic induction method of extensively knowing, the degree of coupling between transmission equipment side and receiver side is very high and can powers expeditiously.Yet, because coupling coefficient need to be remained on to high level, thus if transmission equipment side and receiver side wide apart or be moved, the electric power transfer efficiency between the coil on transmission equipment side and receiver side (being called hereinafter, " efficiency between coil ") will significantly reduce.On the other hand, magnetic resonance method is characterised in that, when Q value is very large, even if coupling coefficient is little, between coil, efficiency can not reduce yet.That is, advantageously eliminated the needs that the axle of transmission equipment side coil and receiver side coil is adjusted, and the high degree of flexibility of the position of transmission equipment side and receiver side and distance is therebetween provided.Q value is to have in the circuit of transmission equipment side or receiver side coil in order to represent the maintenance of energy and the index of the relation between loss (the resonance intensity of indication resonant circuit).After a while efficiency between coil will be described again.

In non-contact electric power conveying system, one of most important key element is, the countermeasure of the heating of reply metallic foreign body.When being no matter electromagnetic induction method or the power supply of the cordless of magnetic resonance method, if there is metal between transmission equipment side and receiver side, produce vortex flow, and metal can be heated.In order to reduce heating, proposed a lot of technology and detected metallic foreign body.For example, the known technology that has use optical pickocff or temperature sensor.Yet supply district is very large when being similar to use magnetic resonance method, it will be very expensive using the detection method of transducer.In addition, when serviceability temperature transducer, the Output rusults of temperature sensor depends near the pyroconductivity it, and this will apply the restriction in design to the equipment of transmission equipment side and receiver side.

Therefore, proposed when there is metallic foreign body between transmission equipment side and receiver side, by checking that the variation of parameter (electric current, voltage etc.) judges whether to exist the technology of metallic foreign body.This technology can reduce costs and design restriction etc. without forcing.For example, patent documentation 1 has proposed during communicating between transmission equipment side and receiver side, detects the method for metallic foreign body based on modulation degree, and patent documentation 2 has proposed to detect based on eddy current loss the method (detecting foreign matter by DC-DC efficiency) of metallic foreign body.

Prior art document

Patent documentation

Patent documentation 1:JP2008-206231A

Patent documentation 2:JP2001-275280A

Summary of the invention

Technical problem

Yet, according to the technology proposing in patent documentation 1, patent documentation 2, do not have consideration to be positioned at the impact of the metal-back of receiver side.When considering the charging of common portable equipment (mobile device), probably some metals (such as metal-back, metal parts etc.) are used in portable equipment and are difficult to conclude that it is caused by " impacts of metal-back etc. " or " sneaking into of metallic foreign body " that parameter changes.For adopting patent documentation 2 as example, what eddy current loss was that pick-up metal foreign matter causes by the metal-back of portable equipment or between transmission equipment side and receiver side is unknown.

In addition, when considering while being similar to the high supply district of the configuration degree of freedom of magnetic resonance method, how metal-back is arranged and changed with respect to supply district according to the equipment on receiver side (such as the portable equipment of portable phone) the impact of the equipment on receiver side.Thereby, with reference to Fig. 1 (a), portable equipment is described with respect to the position of transmission equipment side coil (primary side coil) and the relation between the impact of metallic foreign body to Fig. 1 (c).

Fig. 1 (a) shows wherein portable equipment 4 and is disposed in annular primary lateral coil 1(helical coil) the example of one end (approaching the position of iron core 3), wherein for example by being wound around thin wires 2 around annular core 3, carry out looping primary side coil 1.In this case, for being included in efficiency between primary side coil 1 in portable equipment 4 and the coil between secondary side coil, obtained relatively large value.Fig. 1 (b) shows the example that portable equipment 4 is wherein disposed in one end of primary side coil 1 and has metallic foreign body 5 between transmission equipment side and receiver side.In this case, between coil the value of efficiency in medium level.In addition, Fig. 1 (c) shows the example that portable equipment 4 is wherein disposed in the center of primary side coil 1, and in this case, between coil, the value of efficiency is in medium level.

At Fig. 1 (a), to the example of Fig. 1 (c), using thering is wherein thin wire, be wrapped in the coil of the structure on the iron core 3 with magnet as the example of primary side coil 1, but also obtained similar measurement result from there is the coil of structure of iron-core-free.

Therefore, when portable equipment is disposed in certain position with respect to primary side coil, according to whether having metallic foreign body and produce difference between the value of efficiency between coil as Fig. 1 (a) and situation 1(b), and this difference can be used in detection metallic foreign body.Yet, for example, by making the position of portable equipment closer to the center of annular primary lateral coil, increased portable equipment metal-back impact and when the situation during end in primary side coil is compared with portable equipment, between coil, efficiency can reduce.If the influence degree of metal shell surpasses the influence degree of metallic foreign body, non-contact electric power conveying system can not detect metallic foreign body.Because the metallic foreign body of sneaking between transmission equipment side and receiver side is assumed that the metal-back being less than on receiver side conventionally, therefore when constructing non-contact electric power conveying system by the degree of freedom of the impact of metal-back being taken into account and also keep configuring, the accuracy that detects metallic foreign body becomes problem.

Consider that above-mentioned situation created the disclosure, and by reducing metal-back, the impact of receiver side (primary side) is improved and detects the transmission equipment side that is present in noncontact power transmission system and the accuracy of the metallic foreign body between receiver side.

The solution of problem

An aspect of the present disclosure has adopted such structure:, wherein measure the primary side Q value of the circuit comprise primary side coil and to the structure of the electric power transfer efficiency of secondary side coil, wherein primary side coil and secondary side coil electromagnetic coupled; Q value based on primary side coil is proofreaied and correct electric power transfer efficiency; And the corrected value of the electric power transfer efficiency based on obtained detects and the state of secondary side coil electromagnetic coupled.

According to an aspect of the present disclosure, even there is metal-back in primary side, also can proofread and correct its impact.

The beneficial effect of the invention

According to the disclosure, proofreaied and correct the impact on receiver side (primary side) such as metal-back, make to improve the accuracy that detects metallic foreign body.In addition, can reduce the impact that changes the position of secondary side coil in the plane of primary side coil.

Accompanying drawing explanation

[Fig. 1] (a)～(c) show portable equipment with respect to the diagram of the relation between the position of primary side coil and the impact of metallic foreign body.

[Fig. 2] (a)～(c) show the diagram when the measuring condition when changing the Q value of position measurement primary side of metal.

[Fig. 3] shows according to the key diagram of the summary of the power transmission device using in the non-contact electric power conveying system of the disclosure the first execution mode.

[Fig. 4] is the oscillogram at voltage V1 and the voltage V2 of the power transmission device shown in Fig. 3.

[Fig. 5] shows according to the block diagram of the internal structure example of the power transmission device of the disclosure the first execution mode (primary side).

[Fig. 6] shows according to the block diagram of the internal structure example of the power receiving system of the disclosure the first execution mode (primary side).

[Fig. 7] (a)～(c) show the diagram when the measuring condition when changing the type of the metal-back of portable equipment and measure each parameter.

[Fig. 8] shows according to the flow chart of the example of the metallic foreign body Check processing of the disclosure the first execution mode.

[Fig. 9] (a) and (b) show the circuit diagram of other examples (antiresonant circuit) of resonant circuit.

[Figure 10] shows according to the curve chart of the frequency characteristic of the impedance in the series resonant circuit of the disclosure the second execution mode.

[Figure 11] shows according to the curve chart of the frequency characteristic of the impedance in the antiresonant circuit of the disclosure the second execution mode.

[Figure 12] Figure 12 calculates the circuit diagram of Q value according to the real part from impedance of the disclosure the 3rd execution mode and the ratio of imaginary part.

Embodiment

Describe below with reference to the accompanying drawings and implement embodiment of the present disclosure.To be described in the following sequence.The element common for each figure will be endowed identical reference number, to omit the description of repetition.

1. the first execution mode (detecting unit: between the Q value primary side and coil, efficiency detects the example of metallic foreign body)

2. the second execution mode (Q value arithmetic element: the example of calculating Q value by half-power bandwidth method)

3. the 3rd execution mode (Q value arithmetic element: the example of calculating Q value from the real part of impedance and the ratio of imaginary part)

4. other (various distortion)

<1. the first execution mode >

[introductory statement]

At the first execution mode of the present disclosure (hereinafter, be also referred to as " this example ") in, will describe by using these devices of non-contact electric power conveying system to detect structure and the method for near the conductor such as metal power transmission device or power receiving system.Hereinafter, the conductor detecting such as metal also can be described to " detection metal ".Conductor herein comprises sensu lato conductor, that is, and and semiconductor.

First, the electric power transfer efficiency (efficiency between coil) between transmission equipment side (primary side) and the coil of receiver side (primary side) in the non-contact electric power conveying system of magnetic resonance method will be described in.

By formula (1), provided the theoretical maximum η of efficiency between known coil _max:

[mathematical expression 1]

${\mathrm{\&eta;}}_{\max }=\frac{S^2}{{(1+\sqrt{1+S^2})}^2}.....\left(1\right)$

[mathematical expression 2]

S=kQ.....(2)

[mathematical expression 3]

$\text{Q=}\sqrt{Q_1{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA0000411978670000031.png,HDA0000411978670000081.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2}.....\left(3\right)$

Q represents the Q value of whole non-contact electric power conveying system, Q ₁the Q value that represents primary side, and Q ₂the Q value that represents primary side.That is, in magnetic resonance method, efficiency eta between coil _maxin theory by the coupling coefficient k of the electromagnetic coupled degree as primary side coil and secondary side coil and as the primary side Q value (Q of the Q value of unloaded resonant circuit ₁) and primary side Q value (Q ₂) unique definite.Therefore, even if coupling coefficient k is less, if the Q value of transmission equipment side and receiver side is larger, still can be with high-efficiency transfer electric power.

In using this example of electromagnetic coupled, even if coupling coefficient k is less, by increasing the Q value of the series resonant circuit of primary side coil and secondary side coil, increase the configuration degree of freedom of primary side coil and secondary side coil.For instance, this system is that at least one the Q value that coupling coefficient k by primary side coil and secondary side coil is set to below 0.5 and in primary side coil and secondary side coil is set to more than 100 be designed to.The second execution mode that this is also applicable to describe after a while and the 3rd execution mode.Yet this example must be not limited to above-mentioned numerical example.

Now, by by use formula (1) to formula (3) check metal-back on receiver side impact will have influence on which parameter.

Suppose large primary side coil 1 as shown in FIG. 1 and little secondary side coil.Coupling coefficient k is the parameter that can change according to its physical relation.No. 2008-136311st, Japanese Patent Application Publication, Japanese unexamined patent open (translation of PCT application) 2009-504115 etc. have proposed such primary side structure:, this is configured in and in magnetic resonance method, keeps coupling coefficient k homogeneous, and can be by the well-designed coupling coefficient k homogeneous that makes to primary side.Therefore,, in the disclosure, suppose that coupling coefficient k is retained as homogeneous and will inquires into below Q value.

About the Q value of secondary side coil, secondary side coil is comprised in the metal-back of portable equipment etc., and where therefore no matter portable equipment is placed in large primary side coil, and the physical relation between secondary side coil and metal-back is constant.Large metal is attached to primary side coil, otherwise in the situation that metallic foreign body enters, also thinks that the Q value of secondary side coil remains unchanged.By being similar to side well-designed that magnet is adhered to the planar primary lateral coil relative with desk etc., the impact that can remove at an easy rate desk etc.Therefore, clearly, what be subject to that the metal-back of portable equipment affects is the value of primary side.

Fig. 2 (a)～(c) shows when the measuring condition when changing the position of metal and measure the Q value of primary side.

150mm(is longitudinally) * 190mm(is horizontal) spiral coil as primary side coil 1, around this spiral coil, be wound around twisted wire (the wire diameter φ: 1.0mm), be intertwined with many fine copper wires in this twisted wire as wire.Be considered the 50mm(of metal shell longitudinally) * 60mm(is horizontal) * 0.05mm(thickness) and sheet metal 6 be used in primary side.The sheet metal 6 of two types that use is made by aluminium and stainless steel.Then, when sheet metal 6 is in three positions: the center of (1) primary side coil 1 (Fig. 2 (a)); (2) from center, being offset in a lateral direction (movement) (Fig. 2 (b)) and (3) measured in the end of primary side coil 1 (Fig. 2 (c)) time.

Table 1 shows each position for each metal, the measurement result of the Q value of primary side.

[table 1]

Measurement result shown in table 1 has also verified that the Q value in primary side, according to the position of sheet metal 6 or metal material, sizable change occurs.From above-mentioned formula (1) to (3), the Q value of primary side affects efficiency between coil (eddy current loss) significantly, and therefore, clearly, the reduction (eddy current loss of increase) of efficiency between the variation domination coil of the degree of impact of the variation of the degree of impact of metal-back but not little metallic foreign body, and be difficult to detect little metallic foreign body.

Therefore, the Q value by efficiency and primary side between the dynamic Q value changing in measurement primary side and use coil, checks the threshold value of metal shell being taken into account the impact of primary side and being set

[measuring principle of Q value]

The measuring principle of the Q value of primary side is described with reference to Fig. 3.

Fig. 3 shows according to the summary of the power transmission device (primary side) using in the non-contact electric power conveying system of the disclosure the first execution mode.The circuit of power transmission device 10 shown in Figure 3 means the example of basic circuit structure (in magnetic-coupled situation) of measuring principle of the Q value of primary side.Use the Q value measurement of this circuit to be also that measured equipment is used and to be well-known technology.To circuit structure and the Q value measurement method of power transmission device 10 briefly be described below.

If there is sheet metal near the primary side coil 15 of power transmission device 10, the magnetic line of force passes metal and in metal, causes eddy current.When watching from primary side coil 15, metal and primary side coil 15 are electromagnetic coupled, so that real resistance load is attached to primary side coil 15, thus the Q value of change primary side.Measuring Q value can cause near the metal (electromagnetic coupled state) existing primary side coil 15 to detect.

Power transmission device 10 in this example comprises: the AC power supplies 12 that comprises generation AC signal and signal source 11, capacitor 14 and the primary side coil 15(power main circle of resistive element 13).Resistive element 13 is examples of the internal resistance (output impedance) of AC power supplies 12.The example of capacitor 14 and primary side coil 15(coil) be connected to signal source 11 to form series resonant circuit (example of resonant circuit).Then, the inductance value (L value) of the capacitance of capacitor 14 (C value) and primary side coil 15 is adjusted, so that there is resonance at the frequency place that should measure place.The supply unit that comprises signal source 11 and capacitor 14 is delivered to outside by primary side coil 15 by electric power in non-contacting mode.

If forming primary side coil 15 and the voltage between capacitor 14 of series resonant circuit is the example that V1(is applied to the voltage of resonant circuit), and the voltage between the two ends of primary side coil 15 is V2, by formula (4), represent the Q value of series resonant circuit.

[several 4]

$\frac{V2}{V1}=\frac{2\mathrm{\&pi;fL}}{r_s}.....\left(4\right)$

Rs: the effective resistance at frequency f place

Voltage V1 is multiplied by Q and obtains voltage V2.When sheet metal approaches primary side coil 15, effective resistance rs increases and Q value reduces.Therefore,, when sheet metal approaches primary side coil 15, measured Q value (electromagnetic coupled state) changes.

Conventionally, if the Q value that the Q value of capacitor is Qc and coil is QL, the Q value of resonant circuit is by being related to 1/{(1/Qc)+(1/QL) } represent.Q value for the capacitor 14 measured is designed to fully be greater than the Q value of primary side coil 15, and can ignore its impact on the Q value of series resonant circuit.Yet the Q value of primary side coil 15 can be designed to fully be greater than the Q value of capacitor 14 or the Q value that both can have same degree.

When the AC power supplies 12 when for confirming shown in Figure 4 produces preset frequencies sinusoidal wave, the example of the waveform of the voltage V1 between the voltage V2 between primary side coil 15 two ends and primary side coil 15 and capacitor 14.

In this example, the amplitude of sinusoidal wave voltage V2 is 8.64V, and the amplitude of voltage V1 is 46.4mV, and thereby the amplitude of sinusoidal wave voltage V2 be approximately 186 times of amplitude of voltage V1, and the Q value of series resonant circuit is considered to 186.

Described the series resonant circuit of power transmission device 10, but power receiving system has resonant circuit equally.Therefore Fig. 3 shows the basic circuit on the transmission equipment side that comprises series resonant circuit, as long as and comprise the function of foregoing circuit, can consider that various forms comes for detailed structure.

[electromagnetic coupled condition detection method]

To describe according to the couple state detection method of the use primary side Q value of the disclosure the first execution mode below.

From formula (2), formula (3), calculate efficiency between the coil magnetic resonance method as above, obtain [mathematical expression 5] and [mathematical expression 6].

[mathematical expression 5]

$\mathrm{<figure-callout\; id="2"\; label="k\; Q"\; filenames="HDA0000411978670000031.png,HDA0000411978670000081.png"\; state="\{\{state\}\}">k</figure-callout>}\sqrt{Q_{}}\sqrt{{}_2}=X.....\left(5\right)$

[mathematical expression 6]

$S=\sqrt{Q_1}X.....\left(6\right)$

S in formula (6) is updated to generation in formula (1) and does not comprise Q ₂three variable η _max, Q ₁, X equation.If primary side Q value (Q ₁) and coil between the value η of efficiency _maxbe known, determined value X.By said method, can measure primary side Q value (Q ₁) and by patent documentation 2(referring to [0041] to [0043] etc.) described in technology (to monitor the current value of primary side and current value and the magnitude of voltage of magnitude of voltage and primary side), can measuring coil between efficiency eta _maxvalue.

As shown at formula (5), the value of X is by from efficiency eta between coil _maxvalue in omit the variation of Q value of primary side and the formula that obtains, and therefore by using the value of X to detect metallic foreign body, can reduce the impact of the primary side Q value variation being caused by metal-back.Using formula (6) substitution formula (1) and X is produced as solving object,

[several 7]

$X=-\frac{\sqrt[2]{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}\left(7\right)$

And the value of X can be from two measured variable (Q ₁, η _max) determine in real time.

[the structure example of power transmission device]

Next, will describe according to the concrete example of the power transmission device of the disclosure the first execution mode (primary side).

Fig. 5 shows the block diagram of the detailed internal structure example that is equipped with the power transmission device (primary side) of measuring primary side Q value function.Power transmission device 10 comprises by the testing circuit of above-mentioned electromagnetic coupled condition detection method detection such as the conductor of metal.Power transmission device 10 combines and forms non-contact electric power conveying system with the power receiving system of describing after a while.

Power transmission device 10 comprises electric power delivery controller 21, electric power feed drive device 22, forms capacitor 14 and primary side coil 15, resistive element 23a, 23b for dividing potential drop, 24a, 24b, amplifier 25,27, rectifier 26, rectifier 28 and the analogue-to-digital converters (" ADC " hereinafter) 29 of series resonant circuit.In addition, comprise detecting unit 30 and communication unit 36.When comparing with conventional art, detecting unit 30 and communication unit 36 are new.

In power transmission device 10 in this example, the series circuit of resistive element 23a and resistive element 23b is connected to one end of capacitor 14, and the series circuit of resistive element 24a and resistive element 24b is connected to the other end of capacitor 14.Then, the signal (corresponding to voltage V1) that its voltage is divided into suitable voltage by resistive element 23a and resistive element 23b offers ADC29 via amplifier 25 and rectifier 26.Similarly, the signal (corresponding to voltage V2) that its voltage is divided into suitable voltage by resistive element 24a and resistive element 24b is input to ADC29 via amplifier 27 and rectifier 28.ADC29 converts the analog D C signal by rectifier 26 and rectifier 28 rectifications digital DC signal to and exports this numeral DC signal to detecting unit 30.

Detecting unit 30 is examples of controller, and it is by for example MPU(microprocessing unit in whole or in part) form to control whole power transmission device 10.Detecting unit 30 comprises: Q value arithmetic element 31, current/voltage detecting unit 32, X value arithmetic element 33, memory 35 and function are the determining unit 34 that exports control signal to electric power delivery controller 21 and control the generation of AC voltage.

Q value arithmetic element 31 by by the amplitude of signal corresponding to the voltage V2 at primary side coil 15 two ends with from ADC29 output divided by and the amplitude of signal corresponding to primary side coil 15 and voltage V1 between capacitor 14, calculate primary side Q value (=V2/V1), and export result of calculation to X value arithmetic element 33.Q value arithmetic element 31 also exports result of calculation to electric power delivery controller 21.By the amplitude to each signal by this way, do division, can measure in real time primary side Q value.

Current/voltage detecting unit 32 detects induced voltage (primary side voltage) and the induced current (primary side electric current) producing in primary side coil 15, and exports testing result to X value arithmetic element 33.In addition, communication unit 36 is received in the induced voltage (secondary-side voltage) that produces secondary side coil and the information of induced current (secondary side current) from power receiving system, and current/voltage detecting unit 32 exports this information to X value arithmetic element 33.

X value arithmetic element 33 is examples of corrected value arithmetic element, and calculate from the primary side voltage of current/voltage detecting unit 32 inputs and be used as primary side power with the product of primary side electric current, and the secondary-side voltage that receives by communication unit 36 of calculating and the product of secondary side current are used as primary side power.Then, the ratio that X value arithmetic element 33 is calculated primary side power and primary side power is used as efficiency eta between coil _max.X value arithmetic element 33 is used from the primary side Q value (Q of Q value arithmetic element 31 inputs ₁) and coil between the value η of efficiency _max, according to formula (7), calculate X value, and export this X value to determining unit 34.Incidentally, by current/voltage detecting unit 32, can carry out efficiency eta between coil _maxcomputing.

Determining unit 34 is by the X value from 33 inputs of X value arithmetic element and be stored in the threshold nonvolatile storage 35, and whether result exists the conductor such as metal near determining based on the comparison.For example, if for example, measured X value and threshold value quite (, being 90% when there is no metallic foreign body), and X value is less than 90%, and determining unit 34 can be determined between primary side coil and secondary side coil and has metallic foreign body.Near primary side coil 15, there is not anything or in secondary side coil, do not placing primary side Q value under anything state and the threshold value of X value is measured in advance, and measured value is being stored in memory 35.

Communication unit 36 is examples of primary side communication unit, and communicates with the communication unit of the power receiving system of describing after a while.For example, communication unit 36 is received in the induced voltage (secondary-side voltage) that produces in the secondary side coil of power receiving system and the information of induced current (secondary side current), and to notify power receiving system Q value be measured according to the control of testing circuit 30.As communication standard, for example, can use WLAN or the bluetooth (registered trade mark) of IEEE802.11 standard.Incidentally, can adopt the structure via the secondary side coil transmission information of primary side coil 15 and power receiving system.

[the structure example of power receiving system]

Next, will describe according to the concrete example of the power receiving system of the disclosure the first execution mode (primary side).

Fig. 6 shows the block diagram of the internal structure example of the power receiving system (primary side) that is applied to portable equipment.Power receiving system 40 comprises: the secondary side coil 41 and capacitor 42, rectifier 43, power subsystem 44, power-supply controller of electric 45, load-modulate unit 46, current/voltage detecting unit 47 and communication unit 48 that form antiresonant circuit.The circuit structure of power receiving system 40 is in this example well-known circuit, therefore will be briefly described below.

In power receiving system 40, comprise that the antiresonant circuit of secondary side coil 41 and capacitor 42 is connected to power subsystem 44 via rectifier 43.The inductance value (L value) of the capacitance of capacitor 42 (C value) and secondary side coil 41 is adjusted, so that produce resonance at the frequency place that should measure place.The electric power receiving element consisting of capacitor 42 and rectifier 43 receives electric power from outside by secondary side coil 41 in non-contacting mode.The AC induced voltage of secondary side coil 41 offers power subsystem 44 after converting DC voltage to by rectifier 43.

Power subsystem 44 is by producing supply power voltage to being rectified the voltage level adjustment of the DC voltage obtaining after device 43 conversion, and electric power is offered to load 50 or each piece.For example, load 50 is electronic circuits of capacitor (reserve battery), the processing signal of telecommunication etc.

Power-supply controller of electric 45 is controlled the generation of the supply power voltage that power subsystems 44 carry out and to the supply of electric power of load 50 etc.Power-supply controller of electric 45 is gone back the operation of control load modulating unit 46.

Load-modulate unit 46 is carried out load-modulate according to the control of power-supply controller of electric 45 and is processed.When Q value is by power transmission device 10(primary side) while measuring, primary side Q value changes, thereby causes the primary side at power receiving system 40() the condition of load change under produce error.Therefore, expectation is to measure the load in primary side under the constant condition of the load of primary side.

Therefore, before the load-modulate unit 46 by the resistive element 46R that is connected in series and switch element 46T structure is parallel capacitances connected in parallel to power subsystem 44.Then, when power transmission device 10 is measured Q value, power-supply controller of electric 45 receives via communication unit 48 notice that power transmission device 10 is being measured Q value, and turn on-switch element.Can suppress by the resistance that makes the resistance of resistive element 46R be far longer than load 50 impact of load 50.Therefore, by control, be positioned at power subsystem 44 load-modulate unit 46 before, can be so that the load resistance in primary side remains unchanged when measuring primary side Q value.Therefore, can improve the certainty of measurement of primary side Q value.For instance, the transistor such as power MOS transistor can be used as switch element 46T.

Current/voltage detecting unit 47 detects induced voltage (secondary-side voltage) and the induced current (secondary side current) producing in secondary side coil 41, and exports testing result to communication unit 48.

Communication unit 48 is examples of primary side communication unit, and communicates with the communication unit 36 of power transmission device 10.For example, communication unit 48 to power transmission device 10, and is being measured the notice of Q value by the communication of the induced voltage (secondary-side voltage) producing in the secondary side coil at power receiving system 40 41 and induced current (secondary side current) from power transmission device 10 receptions.The communication standard of communication unit 36 that is applied to power transmission device 10 is applicable equally.

By supposition power transmission device 10, only have electric power conveying function and power receiving system 40 only to have electric power receiving function to describe this example, but the disclosure is not limited to such example.For example, power transmission device 10 can have electric power receiving function, make can receive electric power from outside by primary side coil 15, or on the contrary, power receiving system 40 can have electric power conveying function, makes electric power to be delivered to outside by secondary side coil 41.

[calibration result of the variation of the primary side Q value being produced by metal-back]

The effect that the variation to the primary side Q value being caused by metal-back of describing by carrying out according to the couple state detection method of the disclosure the first execution mode is proofreaied and correct.

Fig. 7 (a)～(c) shows the measuring condition when changing the metal types of the metal-back of portable equipment and measure each parameter.Condition (1) is to be assumed that the situation (Fig. 7 (a)) when relative with primary side when the aluminium mainly being had by primary side (portable equipment 4A).Condition (2) is to be assumed that the situation (Fig. 7 (b)) while sneaking in (1) when little metallic foreign body 5.In (2), from primary side, can see large metal-back, even and therefore sneaked into little metallic foreign body 5, primary side Q value is also almost constant.On the other hand, primary side Q value and coupling coefficient k reduce under the impact of metal-back.In addition, condition (3) is to be assumed that the situation (Fig. 7 (c)) when relative with primary side when the stainless steel mainly being had by primary side (portable equipment 4B).

Table 2 shows the measurement result when measuring each parameter in above-mentioned condition (1) to (3).

[table 2]

From (3) of table 2, clearly, along with making the portable equipment 4A with stainless steel metal shell closer to primary side coil 15, primary side Q value significantly reduces.Metal dimension in above-mentioned table 1 be 50mm(longitudinally) * 60mm(is horizontal), but the metal-back of portable equipment can be slightly larger and be defined as waiting reducing, so the Q value in primary side is assumed that 40.Q value and coupling coefficient k in condition (3) in primary side are assumed that those values in the condition of being approximately equal to (1).The result of calculating efficiency and X value between coil under these conditions has been shown in table 2.

If pay close attention to efficiency between the coil in table 2, clearly, the impact of metal-back is greater than the impact of metallic foreign body, and between the coil in (3) efficiency (57.58070118) lower than efficiency (67.20257032) between the coil of wherein having sneaked in (2) of metallic foreign body.Even if this makes to have set threshold value, be still just difficult to detect accurately metallic foreign body.On the other hand, if pay close attention to X value, wherein sneaked into the value lower (0.383406) in (2) of metallic foreign body.Therefore, the impact of the metal-back when using X value by electromagnetic coupled state deducts, and can improve the accuracy of detection metallic foreign body.Between X value while incidentally, there is metal-back in portable equipment and the X value while there is not metal-back, there is very significant difference.

[metallic foreign body testing process]

Next, with reference to the flow chart description in Fig. 8 according to the example of the metallic foreign body Check processing of the disclosure the first execution mode.

First, the detecting unit 30(of power transmission device 10 is referring to Fig. 5) need to, by scanning the sinusoidal wave frequency that be produced by AC power supplies, search out the maximum Q value in primary side.That is, from the sinusoidal wave frequency of power transmission device 10 outputs, continuously changed to scan the maximum Q value primary side.For example, electric power feed drive device 22(is referring to Fig. 5) produce and export the sine wave (step S1) of arbitrary A Hz and Q value arithmetic element 31 is measured primary side Q value (step S2) according to the voltage V1 of power transmission device 10 and voltage V2.

Detecting unit 30 determines whether measured primary side Q value is greater than the value (being referred to as hereinafter, " register value ") (step S3) being stored in register (example of the temporary storage cell) (not shown) being included in detecting unit 30.Can make working storage (not shown) or memory 35 these values of storage.

In definite processing in step S3, if primary side Q value is greater than register value, detecting unit 30 upgrades register value (step S4) and next sinusoidal wave frequency A Hz is increased to B Hz(step S5).Then, detecting unit 30 is produced and is exported the sine wave of (A+B) Hz by electric power feed drive device 22, to measure primary side Q value in step S2.Then, process and proceed to step S3.

On the other hand, if primary side Q value is less than register value in the definite processing in step S3, detecting unit 30 is determined primary side Q value (step S6).

Detecting unit 30 determines whether determined primary side Q value is exceptional value (step S7).If determined primary side Q value is exceptional value (outside threshold range), the operation (step S8) of detecting unit 30 forced termination power transmission devices 10.Incidentally, can omit the processing in step S7, step S8.

If determined primary side Q value is normal value (within threshold range) in the definite processing in step S7, the electric power that detecting unit 30 starts from power transmission device 10 to receiving system 40 is carried, and X value arithmetic element 33 is also calculated DC-DC efficiency, that is, efficiency (step 9) between coil.

X value arithmetic element 33 is used formula (7) to calculate X value (referring to formula (7)) (step S10) from efficiency between coil and primary side Q value.

Determining unit 34 determines whether the X value calculating is equal to or less than the threshold value Z(step S11 being stored in memory 35).If X value is equal to or less than threshold value Z, determining unit 34 is determined and is had metallic foreign body forced termination transferring electric power (step S12).

On the other hand, if X value is greater than threshold value Z, determining unit 34 is definite there is not metallic foreign body and continues transferring electric power.By carrying out at a certain time interval a series of processing, can in the situation that not affected by metal-back, detect metallic foreign body.That is, determining unit 34 determines whether to have passed the scheduled time (step S13), and if passed the scheduled time, proceeds to step S1 to repeat a series of processing in step S1 to S13.

[effect of the first execution mode]

According to the first execution mode, based on primary side Q value, proofread and correct power transmission device 10(primary side) Q value and the coil of non-contact electric power conveying system between efficiency between efficiency (electric power transfer efficiency) and coil.Then, the fact is the changes of threshold of obtained corrected value (X value) while never barrier being detected, and detects near non-contact electric power conveying system and have metallic foreign body.Therefore, the impact of calibration metal shell on primary side (such as portable equipment), makes to improve the accuracy that detects metallic foreign body.

In addition,, when secondary side coil is placed on the optional position with respect to planar primary lateral coil, can reduce the impact of the change in location of secondary side coil in the plane of primary side coil.

Therefore, can realize user's fail safe and improve availability.

Described in the present embodiment the example comprising the power transmission device 10 of series resonant circuit, but other resonant circuits also can be used as resonant circuit.Fig. 9 (a) and (b) show each example.In the example of Fig. 9 (a), by capacitor 14A being connected to the antiresonant circuit of capacitor 14B and primary side coil 15, construct resonant circuit.In the example of Fig. 9 (b), by capacitor 14B being connected in parallel to the series resonant circuit of capacitor 14A and primary side coil 15, construct resonant circuit.The primary side coil 15 that detecting unit 30 uses obtain from the resonant circuit shown in Fig. 9 (a) and (b) and the voltage V2 between the voltage V1 between capacitor 14A and primary side coil 15 two ends, calculate primary side Q value.Series resonant circuit and other resonant circuits are all as example, and the structure of resonant circuit is not limited to such example.Be similar to power transmission device 10, various resonant circuits also can be applicable to power receiving system 40.

<2. the second execution mode >

In the first embodiment, the Q value arithmetic element 31 of detecting unit 30 is from the voltage V1 between primary side coil and the capacitor of series resonant circuit and the voltage V2 between power main circle two ends, determine Q value, but in the second execution mode, by half-power bandwidth method, determine Q value.

As shown at the curve chart of Figure 10, in half-power bandwidth method, when configuration series resonant circuit, from its middle impedance, be the impedance (Z of resonance frequency f0 _peak) absolute value in frequency band (frequency: f1 to f2) doubly, by formula (8), determine Q value.

[mathematical expression 8]

$Q=\frac{f_0}{f_2-f_1}.....\left(8\right)$

As shown in the curve chart of Figure 11, when configuration antiresonant circuit, from its middle impedance, be the impedance (Z of resonance frequency f0 _peak) absolute value

frequency band (frequency: f1 to f2) doubly, determines Q value by formula (8).

<3. the 3rd execution mode >

Compare with the second execution mode with the first execution mode, the 3rd execution mode is the example that the Q value arithmetic element 31 of wherein detecting unit 30 is calculated Q value from real part and the imaginary part of the impedance of resonant circuit.In this example, by using self-balancing bridge circuit and vector ratio detector to determine real part and the imaginary part of impedance.

Figure 12 calculates the circuit diagram of the self-balancing bridge of Q value according to the 3rd execution mode from the real part of impedance and the ratio of imaginary part.

At the self-balancing bridge circuit 60 shown in Figure 12, there is the structure that is similar to general well-known inverting amplifier.Inverting input (-) and in-phase input end (+) that coil 62 is connected to inverting amplifier 63 are connected to ground.Then, by feedback resistance element 64, negative feedback is applied to inverting input (-) from the output of inverting amplifier 63.In addition the output (voltage V2) that the output of AC power supplies 61, (voltage V1) inputs to coil 62 and inverting amplifier 63 by AC signal is input to vector ratio detector 65.Coil 62 is corresponding to the primary side coil in Fig. 5 or the secondary side coil in Fig. 6.

Self-balancing bridge circuit 60 operates by this way: because negative feedback makes the voltage of inverting input (-) always zero.Because the input impedance of inverting amplifier 63 is large, so the electric current that flows into coil 62 from AC power supplies 61 almost all flows into feedback resistance element 64.Therefore, the voltage that is applied to coil 62 becomes and equates with the voltage V1 of AC power supplies 61, and the output voltage of inverting amplifier 63 equals electric current I and the feedback resistance R of flowing through coil 62 _sproduct.Feedback resistance R _sit is known reference resistance.Therefore, by detecting voltage V1 and voltage V2 and calculating its ratio and determine impedance.Vector ratio detector 65 uses the phase information (dotted line that length replaces) of AC power supplies 61 to using to determine as plural voltage V1 and voltage V2.

In this example, by using the impedance Z of definite resonant circuits such as self-balancing bridge circuit 60, vector ratio detector 65 _lreal part R _lwith imaginary part X _l, and determine Q value from its ratio.Formula (9) and formula (10) show the computing formula of the process of determining Q value.

[mathematical expression 9]

$Z_L=R_L+j{X}_L=\frac{V1}{I}=\frac{V1}{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000411978670000031.png,HDA0000411978670000081.png"\; state="\{\{state\}\}">V</figure-callout>}2}\mathrm{Rs}.....\left(9\right)$

[mathematical expression 10]

$Q=\frac{X_L}{R_L}.....\left(10\right)$

<4. other >

In the of the present disclosure first to the 3rd above-mentioned execution mode, Q value is measured at resonance frequency place, if but allowing slight reduction detection sensitivity, the frequency of measuring Q value place needn't be consistent with resonance frequency, and can use the Q value of measuring at the frequency place of off-resonance frequency.

When the disclosure is applied to electromagnetic induction method, preferably increase the Q value of primary side and/or primary side.Therefore, the change of efficiency between magnetic test coil more easily, that is, and the change of X value.

Using the example of coil without iron core as being described according to primary side coil of the present disclosure and secondary side coil, but also can adopt thin wire to be wrapped in the coil of the structure on the iron core with magnet.

In addition, in the of the present disclosure first to the 3rd execution mode, described and using portable phone as portable equipment, be applied to the example in primary side, but the disclosure is not limited to such example, and applicable to the various portable equipments that need electric power, such as portable music player, digital camera etc.

In addition, the disclosure can also be configured to as follows.

(1) state detection circuit, comprising:

Detecting unit, described detecting unit measurement comprises with the primary side Q value of the circuit of the primary side coil of secondary side coil electromagnetic coupled and to the electric power transfer efficiency of described secondary side coil; By the described Q value of described primary side coil, proofread and correct described electric power transfer efficiency; And according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

(2) according to the electromagnetic coupled state detection circuit of (1),

Wherein, by detecting and whether the state of described secondary side coil electromagnetic coupled exists conductor near determining described secondary side coil.

(3) according to the electromagnetic coupled state detection circuit of (2),

Wherein, the Q value that described Q value is resonant circuit, described resonant circuit comprises described primary side coil and capacitor.

(4) according to the electromagnetic coupled state detection circuit of (3),

Wherein, described detecting unit comprises:

Q value arithmetic element, obtain and be applied to described primary side coil and first voltage between described capacitor of described resonant circuit and put on the second voltage between described primary side coil two ends, and calculate described primary side Q value from the ratio between described the first voltage and described second voltage, described resonant circuit comprises described primary side coil and described capacitor

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the described corrected value of being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

(5) according to the electromagnetic coupled state detection circuit of (3),

Wherein, described detecting unit comprises:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance of the resonance frequency of series resonant circuit from impedance

frequency band is doubly determined described Q value, and described series resonant circuit comprises described primary side coil and described capacitor,

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.(6) according to the electromagnetic coupled state detection circuit of (3), further comprise:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance of the resonance frequency of antiresonant circuit from impedance

frequency band is doubly determined described Q value, and described antiresonant circuit comprises described primary side coil and described capacitor;

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And identifying unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element with when there is no conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

(7) according to the electromagnetic coupled state detection circuit of (3), further comprise:

Q value arithmetic element, is used self-balancing bridge circuit and vector ratio detector to determine real part and the imaginary part component of the impedance of described resonant circuit, and calculates described primary side Q value from the ratio of described real component and described imaginary part component; And

Determining unit, the threshold value setting by near the primary side Q value of measuring in advance to the described primary side Q value of being determined by described Q value arithmetic element and when there is not conductor described primary side coil compares, and determines and the state of described secondary side coil electromagnetic coupled.

(8) according to the electromagnetic coupled state detection circuit of (4),

Wherein, described electric power transfer efficiency is the ratio of primary side power and primary side power, the induced voltage that described primary side power is described primary side coil and faradic product, and described primary side power be described secondary side coil induced voltage and faradic product.

(9), comprising:

Primary side coil, with secondary side coil electromagnetic coupled; And

Detecting unit, measures the primary side Q value of the circuit comprise described primary side coil and to the electric power transfer efficiency of described secondary side coil; Described Q value based on described primary side coil is proofreaied and correct described electric power transfer efficiency; And according to the state of the electromagnetic coupled of the corrected value detection of obtained described electric power transfer efficiency and described secondary side coil.

(10) according to the power transmission device of (9),

Wherein, by the state of detection and described secondary side coil electromagnetic coupled, determine near described secondary side coil, whether there is conductor.

(11) according to the power transmission device of (9),

Wherein, the Q value that described Q value is resonant circuit, described resonant circuit comprises described primary side coil and capacitor.

(12) according to the power transmission device of (11),

Wherein, described detecting unit comprises:

Q value arithmetic element, obtain and be applied to described primary side coil and first voltage between described capacitor of described resonant circuit and put on the second voltage between described primary side coil two ends, and calculate described primary side Q value from the ratio between described the first voltage and described second voltage, described resonant circuit comprises described primary side coil and described capacitor

Correction values calculation unit, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the described corrected value of being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.(13) according to the power transmission device of (11),

Wherein, described detecting unit comprises:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance of the resonance frequency of series resonant circuit from impedance

frequency band is doubly determined described Q value, and described series resonant circuit comprises described primary side coil and described capacitor,

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.(14) according to the power transmission device of (11), further comprise:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance of the resonance frequency of antiresonant circuit from impedance

frequency band is doubly determined described Q value, and described antiresonant circuit comprises described primary side coil and described capacitor;

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And identifying unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element with when there is no conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

(15) according to the power transmission device of (11), further comprise:

Q value arithmetic element, is used self-balancing bridge circuit and vector ratio detector to determine real component and the imaginary part component of the impedance of described resonant circuit, and calculates described primary side Q value from the ratio of described real component and described imaginary part component; And

Determining unit, the threshold value setting by near the primary side Q value of measuring in advance to the described primary side Q value of being determined by described Q value arithmetic element and when there is not conductor described primary side coil compares, and determines and the state of described secondary side coil electromagnetic coupled.

(16) according to the power transmission device of (12),

Wherein, described electric power transfer efficiency is the ratio of primary side power and primary side power, the induced voltage that described primary side power is described primary side coil and faradic product, and described primary side power be described secondary side coil induced voltage and faradic product.

(17) conveying system, comprising:

Power transmission device, wireless transmitting electric power; And

Power receiving system, receives described electric power from described power transmission device,

Wherein, described power receiving system comprises:

Secondary side coil, with the primary side coil electromagnetic coupled of described power transmission device, and

Primary side communication unit, communicates by letter with described power transmission device, and

Wherein, described power transmission device comprises:

Described primary side coil, with the described secondary side coil electromagnetic coupled of described power receiving system, and

Primary side communication unit, communicates by letter with described power receiving system, and

Detecting unit, the information about described power receiving system receiving according to described primary side communication unit, measures the primary side Q value of the circuit that comprises described primary side coil and to the electric power transfer efficiency of described secondary side coil; Described Q value based on described primary side coil is proofreaied and correct described electric power transfer efficiency; And according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

(18) condition detection method, comprising:

Measurement comprises with the primary side Q value of the circuit of the primary side coil of secondary side coil electromagnetic coupled and to the electric power transfer efficiency of described secondary side coil; And

Q value based on described primary side is proofreaied and correct described electric power transfer efficiency, and according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

In addition, can, by the above-mentioned a series of processing in hardware implement execution mode, still also can make software carry out this series of processing.When being carried out this series of processing by software, by the integration procedure that wherein forms software can be carried out to this series of processing to the computer (MPU etc.) in specialized hardware or computer that the program of carrying out various functions has been installed thereon.

For the treatment step of described sequential processing, comprise the processing of carrying out by described order sequential herein, and comprise and do not need processing that carry out chronologically and parallel or that carry out separately (for example, parallel processing or pass through object handles).

The disclosure is not limited to above-mentioned execution mode and naturally can adopts various modifications and application examples under the prerequisite that does not deviate from the spirit and scope described in claim.

List of reference signs

1 primary side coil 4,4A, 4B portable equipment 5 metallic foreign bodies

6 sheet metal 10 power transmission device 11 signal source 12 AC power

13 resistive element 14 capacitor 15 primary side coil

21 electric power delivery controller 22 electric power feed drive device 30 detecting units

31Q value arithmetic element 32 current/voltage detecting unit 33X value arithmetic elements

34 determining unit 35 memory 36 communication unit 40 power receiving systems

41 secondary side coil 42 capacitor 43 rectifier 44 power subsystems

45 power-supply controller of electric 46 load-modulate unit 47 current/voltage detecting units

48 communication units

Claims (18)

1. an electromagnetic coupled state detection circuit, comprising:

Detecting unit, described detecting unit measurement comprises with the primary side Q value of the circuit of the primary side coil of secondary side coil electromagnetic coupled and to the electric power transfer efficiency of described secondary side coil; Described Q value based on described primary side coil is proofreaied and correct described electric power transfer efficiency; And according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

2. electromagnetic coupled state detection circuit according to claim 1,

Wherein, by detecting and whether the state of described secondary side coil electromagnetic coupled exists conductor near determining described secondary side coil.

3. electromagnetic coupled state detection circuit according to claim 2,

Wherein, the Q value that described Q value is resonant circuit, described resonant circuit comprises described primary side coil and capacitor.

4. electromagnetic coupled state detection circuit according to claim 3, wherein, described detecting unit comprises:

Q value arithmetic element, obtain and be applied to described primary side coil and first voltage between described capacitor of described resonant circuit and put on the second voltage between described primary side coil two ends, and calculate described primary side Q value by the ratio between described the first voltage and described second voltage, described resonant circuit comprises described primary side coil and described capacitor

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the described corrected value of being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

5. electromagnetic coupled state detection circuit according to claim 3,

Wherein, described detecting unit comprises:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance at the resonance frequency place of series resonant circuit by impedance

frequency band is doubly determined described Q value, and described series resonant circuit comprises described primary side coil and described capacitor,

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

6. electromagnetic coupled state detection circuit according to claim 3, further comprises:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance at the resonance frequency place of antiresonant circuit by impedance

frequency band is doubly determined described Q value, and described antiresonant circuit comprises described primary side coil and described capacitor;

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element with when there is no conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

7. electromagnetic coupled state detection circuit according to claim 3, further comprises:

Q value arithmetic element, is used self-balancing bridge circuit and vector ratio detector to determine real component and the imaginary part component of the impedance of described resonant circuit, and calculates described primary side Q value by the ratio of described real component and described imaginary part component; And

Determining unit, the threshold value setting by near the primary side Q value of measuring in advance to the described primary side Q value of being determined by described Q value arithmetic element and when there is not conductor described primary side coil compares, and determines and the state of described secondary side coil electromagnetic coupled.

8. electromagnetic coupled state detection circuit according to claim 4,

Wherein, described electric power transfer efficiency is the ratio of primary side power and primary side power, the induced voltage that described primary side power is described primary side coil and faradic product, and described primary side power be described secondary side coil induced voltage and faradic product.

9. a power transmission device, comprising:

Primary side coil, with secondary side coil electromagnetic coupled; And

Detecting unit, measures the primary side Q value of the circuit comprise described primary side coil and to the electric power transfer efficiency of described secondary side coil; Described Q value based on described primary side coil is proofreaied and correct described electric power transfer efficiency; And according to the state of the electromagnetic coupled of the corrected value detection of obtained described electric power transfer efficiency and described secondary side coil.

10. power transmission device according to claim 9,

Wherein, by the state of detection and described secondary side coil electromagnetic coupled, determine near described secondary side coil, whether there is conductor.

11. power transmission devices according to claim 10,

Wherein, the Q value that described Q value is resonant circuit, described resonant circuit comprises described primary side coil and capacitor.

12. power transmission devices according to claim 11,

Wherein, described detecting unit comprises:

Q value arithmetic element, obtain and be applied to described primary side coil and first voltage between described capacitor of described resonant circuit and put on the second voltage between described primary side coil two ends, and calculate described primary side Q value from the ratio between described the first voltage and described second voltage, described resonant circuit comprises described primary side coil and described capacitor

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the described corrected value of being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

13. power transmission devices according to claim 11,

Wherein, described detecting unit comprises:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance at the resonance frequency place of series resonant circuit by impedance

frequency band is doubly determined described Q value, and described series resonant circuit comprises described primary side coil and described capacitor,

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element and when there is not conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

14. power transmission devices according to claim 11, further comprise:

Q value arithmetic element, is used half-power bandwidth method to calculate described primary side Q value, and described half-power bandwidth method is the absolute value of impedance at the resonance frequency place of antiresonant circuit by impedance

frequency band is doubly determined described Q value, and described antiresonant circuit comprises described primary side coil and described capacitor;

Corrected value arithmetic element, when described primary side Q value is that Q1 and described electric power transfer efficiency are η _maxtime, according to following formula calculated correction value:

$-\frac{2\sqrt{\frac{{\mathrm{\&eta;}}_{\max }}{Q_1}}}{{\mathrm{\&eta;}}_{\max }-1}$

And determining unit, the threshold value setting by near the corrected value of measuring in advance to the corrected value being calculated by described corrected value arithmetic element with when there is no conductor described primary side coil compares, and determines the state with described secondary side coil electromagnetic coupled.

15. power transmission devices according to claim 11, further comprise:

Q value arithmetic element, is used self-balancing bridge circuit and vector ratio detector to determine real component and the imaginary part component of the impedance of described resonant circuit, and calculates described primary side Q value by the ratio of described real component and described imaginary part component; And

Determining unit, the threshold value setting by near the primary side Q value of measuring in advance to the described primary side Q value of being determined by described Q value arithmetic element and when there is not conductor described primary side coil compares, and determines and the state of described secondary side coil electromagnetic coupled.

16. power transmission devices according to claim 12,

Wherein, described electric power transfer efficiency is the ratio of primary side power and primary side power, the induced voltage that described primary side power is described primary side coil and faradic product, and described primary side power be described secondary side coil induced voltage and faradic product.

17. 1 kinds of non-contact electric power conveying systems, comprising:

Power transmission device, wireless transmitting electric power; And

Power receiving system, receives described electric power from described power transmission device,

Wherein, described power receiving system comprises:

Secondary side coil, with the primary side coil electromagnetic coupled of described power transmission device, and

Primary side communication unit, communicates by letter with described power transmission device, and

Wherein, described power transmission device comprises:

Described primary side coil, with the described secondary side coil electromagnetic coupled of described power receiving system,

Primary side communication unit, communicates by letter with described power receiving system, and

Detecting unit, the information about described power receiving system receiving according to described primary side communication unit, measures the primary side Q value of the circuit that comprises described primary side coil and to the electric power transfer efficiency of described secondary side coil; Described Q value based on described primary side coil is proofreaied and correct described electric power transfer efficiency; And according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

18. 1 kinds of electromagnetic coupled condition detection methods, comprising:

Measurement comprises with the primary side Q value of the circuit of the primary side coil of secondary side coil electromagnetic coupled and to the electric power transfer efficiency of described secondary side coil; And

Q value based on described primary side is proofreaied and correct described electric power transfer efficiency, and according to the corrected value detection of obtained described electric power transfer efficiency and the state of described secondary side coil electromagnetic coupled.

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